Gustin announced his engagement to Thoma on Saturday with an Instagram post.

Flash star Grant Gustin and his long-time girlfriend LA Thoma are now engaged. The 27-year-old actor announced the news on Instagram on Saturday (29 April).

Gustin and Thoma had intentionally kept their relationship under wraps from the public eye for a long time barring a few photos they shared of one another on social media feeds.

It seems like the onscreen super hero popped the question during their recent beach outing as Thoma can be seen beaming from ear-to-ear - and showing off her engagement ring in the image the 27-year-old actor has shared on Instagram. Gustin has posted the photo without a caption.

As soon as Gustin made the announcement, fans and friends offered congratulatory messages to the couple.

Gustin's longtime friend Leela Rothenberg has shared an image of couple celebrating their engagement during a video chat.

"WHAT WHAT WHAT WHAT WHAT I WAS NOT EXPECTING THIS BUT I LOVE THIS WHAT WHAT WHAT❤️❤️," a fan wrote, while another said, "@grantgust Tell me it's real love and You didn't do it just to save her from Savitar right"

Besides his real life wedding plans, Gustin's character Barry Allen might soon have to prepare for his nuptials in the hit TV series.

"When I knew that they were going to have another proposal, I think it was the sweetest thing," Candice Patton, who plays the character of Iris on the show, told Entertainment Tonight last month. "And I think it's more WestAllen, this proposal. It's at home, it's very casual."

"Barry was kind of re-establishing his confidence in the relationship. Not letting his fear dictate things, but rather let his heart dictate things, which he's always done in the past," Gustin said. "So we're kind of back to true-form Barry, I think. As much as we can be with what he's dealing with right now."